How did Persian commanders and officers communicate with an army composed of dozens of different ethnic groups?

by GermanSpartanic

I've heard from Herodotus's Histories that the Persian army attacking Greece was comprised of Nubians, Thracians, Scythians, Egyptians etc. fighting under a single banner. How were officers able to effectively give orders and communicate?

boredenough2comment

It's a real shame that this hasn't gotten an answer, it's an interesting question and also interesting in why it hasn't been answered.

I wonder if there is a lack of information from the archaic period to give a satisfactory answer?

I have read a little about how Carthage dealt with it's diverse mercenary army in the Punic Wars and would love to know if there were major changes in the 200 years between those wars and the ones you are asking about.